Center-biased double-throw momentary contact switch



g- 31, 1965 H. A. PASSARELLI, JR, ETAL 3,204,071

CENTER-BIASED DOUBLE-THROW MOMENTARY CONTACT SWITCH 2 Sheets-Sheet 1 Filed Dec. 11, 1962 iEEEEkEg I -Pill 4 INVENTORS HENRY A, PASSARELLI JR EARL F REIHMAN M4414? @MMWA A TTORNE Y 1, 1965 H. A. PASSARELLI, JR, ETAL 3,204,071

CENTER-BIASED DOUBLE-THROW MOMENTARY CONTACT SWITCH 2 Sheets-Sheet 2 Filed Dec. 11, 1962 INVENTORS HENRY A. PASSARELLI JR. EARL F. REIHMAN MM '/LZMT% ATTORNEY United States Patent 3,204,071 CENTER-BIASED DOUBLE-THROW MOMEN- TARY CONTACT SWITCH Henry A. Passarelli, Jr., East Providence, and Earl F. Reihmam warwick, R.I., assignors to General Electric Company, a corporation of New York Filed Dec. 11, 1962, Ser. No. 243,770 2 Claims. (Cl. 200-165) This invention relates to a mometary contact switch and particularly to a single-pole, double-throw, remote control momentary contact switch having a low voltage rating.

In manually operated, momentary contact switches, it is desirable to provide means to assure return of the switch actuator to its normal off position upon release thereof by the operator. In the prior art such means have taken the form of a resilient wire or blade which biases the switch actuator to its normal off position. In these prior switches there is a significant danger that failure of the biasing means may cause the switch contacts to remain in their closed position. This may result in ultimate damage to the circuit which is controlled by the switch. Our invention provides means to insure return of the switch actuator to its normal off position even though the biasing means should fail.

It is therefore an object of our invention to provide an improved momentary contact switch.

It is a further object of our invention to provide a momentary contact switch wherein .the danger of the switch remaining in a closed position is minimized.

A still further object of our invention is to provide a single-pole, double-throw, momentary contact switch of low voltage rating having an increased useful life.

In carrying out the objects of our invention in one form thereof, we provide a switch employing a pair of resilient movable contact arms mounted side-by-side in cantilever fashion within a housing. Two separate circuits may be controlled by the switch, one circuit passing through each of the contact arms. The fixed ends of the movable contact arms are secured to opposite ends of the housing in diagonal relation. The free end of each movable contact arm is disposed adjacent one of two fixed contacts which are also mounted on opposite ends of the housing in diagonal relation. A trigger is mounted on the switch housing, above the contact arms, to be pivoted about an axis transverse to the housing and incorporates a pair of integral cams mounted in diagonal relation on opposite sides of the axis. Pivoting of the trigger in either direction causes one of the cams to depress one of the movable contact arms against its respective fixed contact. The trigger additionally provides an integral tongue which extends downwardly into the housing between a Pair of resilient members. These members engage the tongue and upon rotation of the trigger in either direction bias the trigger to a normal off position. Should one or both of these principal biasing members fail, the resilient cantilevered contact arms provide a second biasing force which will return the trigger to its normal ofi position.

Further objects and advantages of our invention may best be understood by reference to the following description taken in connection with the accompanying drawings in which:

FIG. 1 is an exploded perspective view of the momentary contact switch of our invention, some elements being omitted for clarity.

FIG. 2 is an end view of the switch.

FIG. 3 is a front view in partial cross-section taken on line 33 of FIG. 2 showing the position of switch elements upon the closing of one circuit therethroug-h, the norm-a1 off position being shown in dotted lines.

FIG. 4 is a sectional view taken on line 4-4 of FIG.

2 showing the position of switch elements upon the closing of a second circuit therethrough.

FIG. 5 is a sectional view taken on line 5--5 of FIG. 3.

FIG. 6 is a sectional view taken on line 6-6 of FIG. 3.

FIG. 7 is a bottom view of the trigger of our invention.

Referring now to the drawings, FIG. 1 shows a housing 10 enclosing arectangular recess. A cover 11, normally received in the top of housing 10 so that longitudinal portions 11a rest on the longitudinal top surfaces 10a of housing 10, is shown in an inverted position. When the switch is assembled, grooves 1:2 formed in both sides of cover 11 are juxtaposed bearing recesses 13 formed in the side walls of housing 10. A trigger 14 is mounted pivotally in the top of housing 10 with its pivots 15 resting in recesses 13. The grooves 12 confine the rotation of trigger 14 within the cover 11, the handle 16 of trigger 14 extending upwardly through aperture 17 in the cover. Centrally affixed in the base of housing 10, is a U-shaped spring or member 18 for biasing the trigger 14. The upstanding members 19 and 20 of spring 18 engage tongue21 of trigger 14 urging the trigger to a central off position. As shown in FIG. 2, a bracket 22 of sheet metal or other suitable material secures cover 11 to the housing 10 by means of flanges 23 which are integrally formed on each end of the bracket and are secured beneath projections 24 of housing 10.

As can be seen in FIGS. 3-6, 'a pair of fixed contacts 25 and 26 are mounted on conductive elements 27 and 28, respectively, within housing 10. The elements 27 and 28 are mounted on opposite end walls of housing 10 on opposite sides thereof in diagonal relation to one another. I

A pair of resilient movable contact arms 29 and 30 are also mounted within the housing 10 in a diagonal relationship similar to that of the fixed contacts. The resilient contact arms 29 and 30 may be. of any resilient conducting material and are generally L-shaped. The short legs of the L are atfixed vertically to the ends of the housing adjacent vertical portions of conductive elements 27 and 28 while the long legs extend horizontally across the housing 10. The resilient contact arms 29 and 30 include contacts 31 and 32 respectively, carried at the free end-s of the arms and disposed immediately above the fixed contacts 25 jand 26.

Integral insulating portions or separators 3 3 and 34 of housing 10 are providedbetween conductive element 27 and contact arm 30 and between conductive element 28 and contact arm 29 respectively to provide electrical clear} and 32 completes the other.

The U-shaped spring 18 is affixed centrally with the housing 10, to the bottom thereof, by any suitable means such as eyelet 35 as shown in FIGS. 4 and 5. The inside bottom surface of the housing 10, is formed at 36 and 37 to provide achannel in which the central fiat portion of spring 18 resides, thereby preventing rotation of the spring. As mentioned above resilient members 19 and 20, provided by spring 18, extend upwardly from the bottom of the housing on either side of the tongue 21 of trigger -14 urging the trigger to its central 01f position as shown in dotted lines in FIG. 3. Members 29 and 30 are tapered, as best seen in FIG. 5, from bottom totop to provide for a soft feel and to elfect distribution of stresses along the entire length of the resilient arms. In one experiment, -a spring member of annealed spring steel using this design continued to function normally after 70,000 switch cycles, untapered spring members used previously having had an average life of approximately 6,000 cycles.

Trigger 14 is pivotally secured to the housing by cover 11 and bracket 22. The cover 11 provides a pair of shoulders 38 and 39 (see FIGS. 1 and 4) which limit the upward motion of resilient contact arms 29 and 30 when the switch is in its normal off position by engagement with the upper surfaces of the arms.

In addition to the tongue 21, the lower portion of trigger 14 provides a pair of integrally formed earns 40 and 41, 'as best seen in FIG. 7. Cams 40 and 41 are diagonally arranged on trigger 14 to be disposed above corresponding movable contact arms 29 and 30. As seen in FIGS. 3 and 4, the rotation of trigger 14 in either directlon brings one of the cams 40 or 41 into engagement with its corresponding contact arms 29 or 30 to depress the contact arm into engagement with its respective fixed contact 25 or 26. The diagonal relation of earns 40 and 41 provide equal fulcrum arms for trigger 14 thereby requiring equal force for the closing of either contacts 25 and 31 or contacts 26 and 32 and also assuring an equal biasing force to return the trigger to its normal, central, off position.

To operate the switch, handle 16 of trigger 14 may be rotated to the left in a countercloskwise direction as viewed in FIG. 3, to close the movable contact 31 against fixed contact 25. Upon the application of force to the left on handle 16, the trigger 14 rotates about pivots in recesses 13 so as to move cam 40 downwardly to engage the movable contact arm 29 and depress it against its upward bias, thereby completing a circuit through contacts and 31.

As the trigger 14 is rotated counterclockwise, tongue 21 presses resilient .rnember 20 of spring 18 to the right, to a biased position, as seen in FIG. 3. In this position resilient member 20 urges tongue 21 back to its normal central oif position and therefore also tends to rotate trigger 14 in a clockwise direction about pivots 15.

Also, it can be seen that resilient contact arm 29 urges cam 40 upwardly, thereby tending to rotate trigger 14 to its normal off position. Should member 20 fail in any manner, as for example by breaking or excessive bending, which would preclude its biasing relationship with respect to tongue 21, the resiliency and upward bias of movable contact arm 29 against the cam 40 will rotate the trigger 14 back to its normal central position. If resilient movable contact arm 29 is normally biased slightly above the horizontal, a greater rotary force is produced than when contact arm 29 is merely positioned horizonally across housing 10. Thus, it can be seen that in normal operation two biasing forces urge the trigger 14 to its normal central off position, i.e., resilient member 20 tends to rotate the trigger 14 due to its engagement with tongue 21 and resilient contact arm 29 urges the trigger 14 by means of its engagement with cam 40.

When the closing of the circuit through fixed contact 26 and movable contact 32 is desired, rotation of the handle 16 of trigger 14 to the right, in a clockwise direction, as shown in FIG. 4, produces an operation similar to that set forth above. In this instance cam 41 depresses movable contact arm 30 so as to bring contact 32 against fixed contact 26. The action also causes member 19 of spring 18 to be pressed tothe lefit by trigger tongue 21. The diagonal relationships of the fixed and movable contact pairs as well as the diagonal relation of the cams 40 and 41 of trigger 14, provide a compact momentary contact switch capable of controlling either of two circuits, as well as providing equal fulcrum arms for trigger 14. The provision of two biasing forces which urge the trigger 14 to its normal 0 position, minimizes the possibility of the trigger remaining in the on position should the spring 18 fail. The resilient cantilevered movable contact arms 29 and 30 and their cooperation with the diagonally disposed earns 40 and 41, provide a safety feature to assure return of the trigger 14 to its central off posltion.

While we have shown and desccribed a specific embodiment of our invention we do not desire our invention to be limited to the particular construction shown and described. Instead, we intend, by the appended claims, to cover all modifications within the spirit and scope of our invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

' 1. A double-throw, momentary contact switch compris- (a) ahousing;

(b) first and second fixed contacts mounted within said housing on opposite ends thereof;

(c) first and second movable resilient contact arms mounted on said opposite ends of said housing and extending across said housing, each of said contact arms having its free end disposed adjacent to a cordesponding one of said fixed contacts;

(d) a trigger mounted on said housing for pivotal movement about an axis transverse to said contact arms comprising:

(aa) first and second earns disposed on opposite sides of the axis each adjacent a corresponding one of said contact arms whereby pivoting of said trigger in a first direction depresses said first contact arm against said first fixed contact and pivoting of said trigger in a second direction depresses said second contact arm against said second fixed contact, and

(bb) a tongue extending along the longitudinal axis of said trigger into said housing; and

(e) a pair of resilient members disposed on opposite sides of said detent and engaging said detent upon the pivoting of said trigger in either of said directions for providing a biasing force urging said trigger to a central position;

' (f) said contact arms when depressed providing a second biasing force to urge said trigger to a central position.

2. Adouble-throw, momentary contact switch comprising:

(a) a rectangular housing having a pair of bearing recesses centrally formed at the top of the longitudirral sides thereof and a pair of integrally formed projections formed on each end thereof;

(b) a cover received within the top of said housing having a central aperture and a pair of grooves formed on the longitudinal sides thereof juxtaposed said bearing recesses;

(c) a bracket having a central aperture and a pair of end flanges for securing said cover to said housing by engagement of said flanges with said projections;

(d) first and second fixed contacts mounted within said housing adjacent diagonally opposite corners thereof;

(e) first and second movable resilient contact arms mounted adjacent the other diagonally opposite corners of said housing and extending across said housing parallel to the longitudinal dimension of said housing, each of said contact arms having its free end disposed adjacent to a corresponding one of said fixed contacts;

(f) a trigger mounted in said housing comprising:

(aa) a pair of integral, axially aligned, pivots adapted to rest in said bearing recesses and confined by said grooves to permit pivotal movement of said trigger about said pivots,

(bb) ahandle extending upwardly through said apertures for actuation of said trigger,

(cc) first and second cams disposed in diagonal relationship on opposite sides of said pivots, each adjacent a corresponding one of saidmovable contact warms whereby pivoting of said trigger in a first direction depresses said first resilient contact arm against said first fixed contact and pivoting of said trigger in a second,

5 6 direction depresses said second resilient contact References Cited by the Examiner arm against said second fixed contact, and (dd) a tongue on the bottom of said trigger and UNITED STTES PATENTS extending into said housing; and 3 9/ 32 Avaklan 200-1 (g) a U-shaped spring having its bight portion aflixed 5 2,411,036 11/36 Farm at a1 200-6 in the bottom of said housing and a pair of tapered 2,966,559 6/57 Meyer 200-153 resilient members extending upwardly to engage FOREIGN PATENTS opposite sides of said detent to urge said tnigger to a central position upon the pivoting of said tnigger in 77,002 5/32 Swedeneither of said directions; 10 (h) said contact arms, when depressed, providing a BERNARD GILHEANY Prlmary Examiner second biasing force to urge said trigger to a central position. 

1. A DOUBLE-THROW, MOMENTARY CONTACT SWITCH COMPRISING: (A) A HOUSING; (B) FIRST AND SECOND FIXED CONTACTS MOUNTED WITHIN SAID HOUSING ON OPPOSITE ENDS THEREOF; (C) FIRST AND SECOND MOVABLE RESILIENT CONTACT ARRMS MOUNTED ON SAID OPPOSITE ENDS OF SAID HOUSING AND EXTENDING ACROSS SAID HOUSING, EACH OF SAID CONTACT ARMS HAVING ITS FREE END DISPOSED ADJACENT TO A CORDESPONDING ONE OF SAID FIXED CONTACTS; (D) A TRIGGER MOUNTED ON SAID HOUSING FOR PIVOTAL MOVEMENT ABOUT AN AXIS TRANSVERSE TO SAID CONTACT ARMS COMPRISING: (AA) FIRST AND SECOND CAMS DISPOSED ON OPPOSITE SIDES OF THE AXIS EACH ADJACENT A CORRESPONDING ONE OF SAID CONTACT ARMS WHEREBY PIVOTING OF SAID TRIGGER IN A FIRST DIRECTION DEPRESSES SAID FIRST CONTACT ARM AGAINST SAID FIRST FIXED CONTACT AND PIVOTING OF SAID TRIGGER IN A SECOND DIRECTION DEPRESSES SAID SECOND CONTACT ARM AGAINST SAID SECOND FIXED CONTACT, AND (BB) A TONGUE EXTENDING ALONG THE LONGITUDINAL AXIS OF SAID TRIGGER INTO SAID HOUSING; AND (E) A PAIR OF RESILIENT MEMBERS DISPOSED ON OPPOSITE SIDES OF SAID DETENT AND ENGAGING SAID DETENT UPON THE PIVOTING OF SAID TRIGGER IN EITHER OF SAID DIRECTIONS FOR PROVIDING A BIASING FORCE URGING SAID TRIGGER TO A CENTRAL POSITION; (F) SAID CONTACT ARMS WHEN DEPRESSED PROVIDING A SECOND BIASING FORCE TO URGE SAID TRIGGER TO A CENTRAL POSITION. 